His argument seems to be based on the assumption that Trump will lose the popular vote (reasonably likely) and also the vote in the electoral college, and that the Republicans will then break the system to deliver the result they want.
But the way that the system is set up, an electoral college win for Trump (or any Republican candidate) is reasonably plausible. Because of the bizarre way the American political system is engineered, the winner of the presidency tends to be determined by voters in a handful of states. If you can rig things to swing those states your way then, under the existing rules, your guy wins. And the Republicans have invested huge amounts of effort in rigging things so that the vote goes their way where it counts.
So, yes, Trump will probably lose the popular vote for the third time. But the rules will likely say that he wins anyway, and those are (if you overlook the shenanigans aimed at neutering opposing votes at the state level) the same rules that have been in force in every previous election.
So what happens in that case? Yes, the majority of voters know that they were denied what they wanted. But – just as in 2000 and 2016 – the Republicans can say “Sorry, the rules say we won. Live with it.”
We know that the rules suck, that demographics and a historical devil’s bargain has made it possible for a minority to elect the president and other representatives (members of that minority, by the way, are quite happy with this state of affairs). But it’s a lot harder to stir up outrage when the election gets stolen ‘by the book’, just as it has been on two previous occasions, than when one side flagrantly throws procedure out the window to force home their candidate. And if past elections are any guide, I think the Republicans won’t need to put their thumb on the scale at the electoral college level to get the result they want.
Incidentally, it’s also worth considering the other scenario, where by some miracle the Democrats get their shit together enough to pull off an electoral college win. In that case, you again have a large angry minority who “know” that they should have won, just as they “know” they won the 2020 election. And while they may have more or less sucked it up once, if this pesky democracy thing gets in the way of their right to rule a second time, that’s a recipe for real trouble.